20491355 has 4 divisors (see below), whose sum is σ = 24589632. Its totient is φ = 16393080.

The previous prime is 20491351. The next prime is 20491369. The reversal of 20491355 is 55319402.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20491355 - 2² = 20491351 is a prime.

It is a super-3 number, since 3×20491355³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20491351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2049131 + ... + 2049140.

It is an arithmetic number, because the mean of its divisors is an integer number (6147408).

Almost surely, 2^20491355 is an apocalyptic number.

20491355 is a deficient number, since it is larger than the sum of its proper divisors (4098277).

20491355 is an equidigital number, since it uses as much as digits as its factorization.

20491355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4098276.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 20491355 is about 4526.7377878556. The cubic root of 20491355 is about 273.6467066492.

The spelling of 20491355 in words is "twenty million, four hundred ninety-one thousand, three hundred fifty-five".